1. Field of the Invention
The present invention relates to a method and apparatus for enhancing the detection of various entities and objects using dieletrokinesis. In particular, the instant invention is directed to a method and apparatus for locating various entities, including animate human beings and animals, as well as inanimate objects, such as for example, certain types of plastics, by observing and detecting a force and subsequent resulting torque, acceleration, vibration or other measurable quantifiable manifestation of the force created by the non-uniform three-dimensional electric field spatial gradient pattern exhibited uniquely by the entity or object and being detected by the device of the present invention as used by the device""s human operator. According to the present invention, incorporation of laser energy produces a localized region by which the dielectrophoresis force and torque are significantly increased, thereby enhancing detection when compared to devices that do not use lasers.
2. Description of Related Art
The detection of animate entities and inanimate objects presence and/or absence, irrespective of the presence of intervening vision-obstructing structures, electromagentic interference (EMI), weather conditions, and the like, has uses in diverse applications, including law enforcement, military operations, firefighting and rescue, emergency services, transportation security in pre-boarding airplanes, trains and automobiles, construction (new and old), anti-shoplifting protection, and various other security and non-security related fields and operations.
My prior U.S. Pat. No. 5,748,088, entitled xe2x80x9cDevice and Method Using Dielectrokinesis to Locate Entitiesxe2x80x9d, issued May 5, 1998, the disclosure of which is incorporated herein by reference in its entirety, describes the use of a phenomenon known as dielelectrophoresis and resulting dielectrokinesis to detect the presence and/or absence of entites regardless of whether the entities being detected are visually obscured.
In summary, as described in detail in U.S. Pat. No. 5,748,088, dielectrophoresis describes the force and subsequent torque mechanical behavior of initially neutral matter that is dielectrical polarization charged via induction by external spatially non-uniform electric fields. The severity of the spatial non-uniformity of the electric field is measured by the spatial gradient, i.e., spatial rate of change, of the electric field. The fundamental operating principle of the dielectrophoresis effect is that the force (or torque) generated always seeks to point in the same direction, i.e., toward the maximum local electric field gradient, independent of time or sign (+/xe2x88x92).
The dielectrophoretic force depends upon five factors that are multiplied together to arrive at the force. These factors include: shape and volume of the initially neutral matter; the relative polarizability of the neutral matter and the surrounding media (e.g., air, air plus barriers, water vapor, etc.); the external electric field; and the spatial gradient of the external electric field. See, e.g., H. A. Pohl, Dielectrophoresis, Cambridge University Press (1978).
The device described in U.S. Pat. No. 5,748,088 uses the force resulting from the non-uniform electric field squared spatial gradient three-dimensional pattern exhibited uniquely by an entity to indicate the precise location and direction of the subject entity relative to the device""s operator. The electrokinetic effect known as dieletrophoresis is used to induce a force and subsequent resulting torque on an antenna and other component parts of the device to provide a rapid directional location indication of the subject entity.
Additionally, my co-pending U.S. patent application Ser. No. 09/071,825, entitled xe2x80x9cInanimate Entity Line-of-Bearing Location Method Via Linking Material-Specific Non-Uniform Static Electrification Spatial Gradient Pattern to Dielectrophoresisxe2x80x9d, filed May 4, 1998, and U.S. patent application Ser. No. 09/071,806, entitled xe2x80x9cAnimate Entities Line-of-Bearing Location Device and Method Linking Species Specific Non-Uniform Electric Field Pattern of Heart ECG to Dielectrophoresisxe2x80x9d, filed May 4, 1998, the disclosures of which are incorporated herein by reference in their entireties, describe the use of dielectrophoresis to detect the location of inanimate materials and animate entities by coupling the non-uniform electric field spatial gradient pattern via dielectrophoresis to a characteristic force and subsequent torque on a high aspect ratio (length/radius) antenna and selective dielectric polarization matching and filtering components in a locating device giving a real-time updated line-of-bearing to the entity or material maximum surface electric field spatial gradient and hence to the entity or object itself, even if an entity is located behind vision-obscuring barriers made of metals, dielectrics, plastics, earth, wood, etc. and/or EMI is present.
However, the method and device of U.S. Pat. No. 5,748,088, U.S. patent application Ser. No. 09/071,825 and U.S. patent application Ser. No. 09/071,806 have certain limitations relating to ultimate range (i.e., maximum distance of detection), strength of force and subsequent torque manifestation, and the line-of-bearing locator response time. Accordingly, what is needed is a means for improving and enhancing the effectiveness of known detection devices that rely on dielectrokinesis for detecting entities and objects.
The present invention provides an improved and enhanced method and apparatus using dielectrokinesis to locate objects and entities that overcomes the limitations attendant with previous dielectrokinetic detection devices and is an improvement over my prior inventions described in U.S. Pat. No. 5,748,088 and U.S. patent application Ser. Nos. 09/071,825 and 09/071,806. In particular, the present invention uses laser energy to enhance the dielectrokinetic effect by creating a localized region of significantly higher dielectric constant via air""s absorption of the laser""s radiation and other properties which, in turn, significantly increases the dielectrophoretic force and resulting torque, and lowers the response time by preferentially directionally orienting or channeling the non-uniformity of the electric field line generated by the entity or object target towards the laser beam region.
Dielectrophoresis is one of five known electrokinetic effects (the other four being electrophoresis, electro-osmosis, Dorn effect, and streaming potential) and describes the forces affecting the mechanical behavior of initially neutral matter that is dielectrically polarized by induction via spatially non-uniform electric fields. The spatial non-uniformity of an electric field can be measured by the spatial gradient of the electric field. The dielectrophoresis force depends non-linearly upon several factors, including the dielectric polarizibility of the surrounding medium (air plus any intervening walls, trees, etc.), the dielectric polarizibility and geometry of the initially neutral matter (device""s antenna and other component parts of the device), and the spatial gradient of the square of the target""s local electric field distribution as detected at the device""s antenna and other component parts. The spatial gradient is measured by the dielectrophoresis force produced by the polarization charge on the device""s antenna and other component parts, and this force is a constant direction seeking force always pointing (or trying to point) the device""s antenna and other component parts toward the maximum gradient in the three-dimensional non-uniform electric field squared spatial gradient pattern uniquely exhibited by a predetermined entity type.
The constant direction seeking force is highly variable in magnitude as a function of the angular position and radial position of the entity-to-be-located with respect to the device""s antenna and other component parts of the device, and upon the effective dielectric polarizibilities of the intervening medium (like air) and of the materials used in the device""s antenna and other component parts. The following equations define the dielectrophoresis forces wherein Equation 1 shows the force for spherical initially neutral objects (spherical antenna and the device""s other component parts), and Equation 2 shows the force for cylindrical initially neutral objects (cylindrical antenna and the device""s other component parts).
F=2(xcfx80a3)xcex50K1(K2xe2x88x92K1)/(K2+2K1)∇|E0|2xe2x80x83xe2x80x83Equation 1
F=L/a(xcfx80a3)xcex50K1(K2xe2x88x92K1)/(K2+K1)∇|E0|2xe2x80x83xe2x80x83Equation 2
Where:
F is the dielectrophoresis force vector detected by the antenna and the device""s other component parts;
a is the radius of the sphere or cylinder;
L is the length of the cylinder (L/a is the so-called axial ratio);
xcex50 is the permittivity constant of free space;
K2 is the dielectric constant of the material in the sphere or cylinder;
K1 is the dielectric constant of fluid or gas, (air) surrounding both the entity and the antenna and the device""s other component parts;
E0 is the electric field produced by the entity as detected by the antenna and the device""s other component parts; and
∇is the spatial gradient mathematical operator.
It should be noted that the term xe2x80x9cantennaxe2x80x9d as used in this context includes (in a very real sense) all of the components present in the device of the present invention, including the living human operator. To this extent, the dielectric constant of the materials that make up the locator and the living human operator of the present invention all determine the overall value of K2 in the above equations. These materials are not arranged in a uniform spherical or cylindrical shape, and therefore the exact value of K2 and the functional relationship of K2 to K1 are difficult, if not impossible, to determine in a closed form of a mathematical equation. In a practical sense, experimentation has shown (and is continuing to show) the types and placement of dielectric materials needed to produce a maximum dielectrophoretic force and subsequent resulting torque, acceleration, vibration or any other measurable quantifiable manifestations of the force for precisely locating different types of entities. The following table lists some of the dielectric materials possibly used in the locator (K2 values) and/or surrounding (such as air, water, walls, etc.) and the dielectric constants for these materials are:
These operating principles involve using the above-mentioned forces to point an antenna toward the maximum spatial gradient of the local electric field, to thereby indicate the direction toward an unseen entity.
According to the present invention, the performance of devices such as those described in U.S. Pat. No. 5,748,088 and U.S. patent application Ser. Nos. 09/071,825 and 09/071,806 is significantly improved and enhanced by the inclusion of laser energy directed parallel to the longitudinal axis of the antenna of the device. In particular, it has been found that inclusion of laser energy transmitted in a direction parallel to the longitudinal axis of the antenna provides significant improvement in the ultimate range (i.e., maximum range of detection), strength of force and subsequent torque manifestation, and the ultimate speed of the locator response.
As is well known, a laser is a device that generates coherent, nearly single wavelength (and frequency), highly directional electromagnetic radiation emitted in the range from submillimeter through ultraviolet and x-ray wavelengths. Light beams produced by lasers are highly coherent and monochromatic. Strong spatial coherence extends over the beam cross section, and the coherence length along the direction of propagation may be from millimeters to many meters long. In addition to measuring coherence between light at two points separated transversely (cross section) to the direction of the laser beam""s propagation, measurements can also be made of mutual coherence between light at points separated along the direction of propagation. This allows one to define a coherence length Lc such that strong coherence is measured when the separation between the two sampling points is less than Lc. A related coherence time can be defined as tc=Lc/c. Measurement of Lc or tc yields information on the frequency spread of the wave xcex94f, wherein xcex94f≈1/tc.
There are three major types of lasers that are classified based on their light-amplifying substance: (1) solid lasers; (2) gas lasers; and (3) liquid lasers. Examples of solid lasers include semiconductor lasers, crystal lasers, glass lasers. Semiconductor lasers, also called injection lasers, have a small cube of a semiconductor as their light-amplifying substance. A common material used is gallium arsenide. The semiconductor includes two layers that differ in their electric charge. Current passing through the semiconductor produces a continuous beam of coherent light along the junction between the two layers. Semiconductor lasers (also known as laser diodes) convert electricity into coherent light very efficiently. The small size of semiconductor lasers makes them very useful. Schematic drawings of semiconductor, liquid and gas lasers are shown, for reference, in FIG. 6.
According to the present invention, orienting a laser light beam or beams parallel to the longitudinal axis of the locator device antenna, has significantly improved the ultimate range, strength of force and resulting torque manifestation and ultimate speed of the locator response of known locator devices that rely on the dielectrokinesis phenomenon.
The laser enhances the performance of the dielectrokinetic locator devices because the laser light is partially absorbed by the air and usually nearly completely by barrier materials. This partial absorption by air produces electronic and/or thermal excitation absorption. The excitation, thus produced, provides a localized (to the region where the laser beam exists) region of significantly higher dielectric constant and other properties which, in turn, significantly increases the dielectrophoresis force and torque, while concurrently lowering the response time by preferentially directionally orienting or converging the non-uniformity of the electric field line generated by the entity or object target, towards the laser light beam region. The laser beam is characterized by its wavelength, power, coherence length and beam shape (e.g., Gaussian, focused Gaussian, etc.) all of which affect the level of enhancement observed for the dielectrokinesis force and torque provided by the invention.
In addition, it has been observed that the level of laser enhancement of the dielectrokinesis force and torque depends upon the number of lasers (i.e., larger effective volume of partially absorbed beams) and the specific geometrical arrangement of the lasers (i.e., increased convergence of electric field spatial gradient). As will be described in detail herein, multiple lasers are simultaneously operating while they are also directly attached to the entity detection device itself. For a given number of lasers, the optimum geometrical arrangement for maximum laser enhancement is the arrangement with the highest symmetry (e.g., a line for two lasers, a triangle for three lasers, a square for four lasers, etc.).
In accordance with the invention, an operator holds the locator device in hand, and through a handle, the locator device is electrically connected to the operator. The operator is partially electrically grounded (through the operator""s feet), and thereby the individual human operator body""s capacitance (C) and resistance (R) to true ground are connected electrically to the handle of the locator device. Ranges for individual human body""s C have been measured as 100 pF to 400 pF and for individual human body""s R have been measured as 0.03 Kxcexa9 to 1 Mxcexa9. Thus, the generalized electrical parameter (the polarization charge pattern induced on the device by the electric field spatial gradient of the entity in this case, but also electric field, current and voltage) exponential decay time (=RC) constant range for the variety of human being bodies potentially acting as locator device operators is about 3 to 400 xcexc seconds. This decay time constant is greatly increased through an externally connected series resistor of up to 100 Kxcexa9 and parallel capacitor up to 0.01 mF, which results in an effective human operator""s exponential decay time constant up to 1 to 10 seconds.
This enables dielectrophoretic forces caused by the induced polarization charge pattern on the locator device antenna and other component parts to be detected, replenished instantly and locked onto since the force is replenished faster than the induced polarization charge pattern on the device can decay away to true ground through the operator""s body. This effect is called, and is using, the spatially self-correcting nature of the dielectrophoretic force (always pointing or trying to point to the maximum of an entity""s electric field three-dimensional squared spatial gradient pattern, which in the case of inanimate entities, may be static electrification induced).
The locator device is held in a balanced, few degrees down tilt from the exactly horizontal state, and the operator scans the locator device in a constant speed uniform linear motion back and forth. An antenna extends from the front of the locator device and is acted on along with the device""s other components by the aforementioned forces. These forces create a subsequent resulting torque around a well defined pivot line which tends to make the locator device""s antenna and the device""s other component parts point toward the maximum spatial gradient of the square of the non-uniform electric field uniquely exhibited by any target entity within the range of the locator device.
Four internal N-channel J-FETs (field effect transistors) are connected to the locator device""s antenna and operate in their non-linear range to effectively change the antenna""s length. Three of these FETs are arranged in modules that are equidistant from the antenna""s longitudinal axis and are spaced 120xc2x0 apart. The fourth FET is arranged in a module below the axis and to the rear of the locator device. Three potentiometers are provided on the first three modules to adjust the current levels through the first three FETs and thereby tune the locator. The gain and frequency response of the fourth FET is adjusted by a six position switch connected to the base of an NPN transistor. By changing the frequency response of the locator device, the device is tuned to reject the higher frequency electromagnetic signals and noise from all external sources, including those sources associated with the human operator himself in order for the locator device to interact with and respond to only the three-dimensional non-uniform electric field squared spatial gradient pattern exhibited uniquely by a predetermined entity type.
While scanning the locator device in a constant speed uniform linear motion back and forth in front of a known or reference entity, the operator changes the six position switch until a maximum force and subsequent resulting torque is detected and used to aim the antenna and the device""s other component parts toward the target entity. After selecting the setting of the six position switch, the operator adjusts the gain of the first three FETs until the locator device points or tries to point directly at the target entity. For different entities, different dielectric materials are used for the antenna and other component parts. Examples of detectable entities include metals, plastics, polymers and other inanimate materials. Continued research on the instrument has yielded positive results in the instrument""s ability to be tailored both as a geometrical design and with respect to materials of construction to specifically detect a variety of different target entities.
The operation of the locator device described above is enhanced by positioning one or more laser emitting devices such that the beam or beams are emitted in a direction parallel to the longitudinal axis of the locator device antenna. In cases where more than one laser is used, it is preferably to optimize their affect on the dielectrokinetic force by arranging the beams in an optimal geometrical configuration, such as, for example, where three lasers are used the beams are arranged in a triangular configuration, i.e., the lasers are arranged to be at the points of an equilateral triangle emitting their beams transversely of plane of the triangle.
Accordingly, it is an object of this invention to enhance the dielectrokinetic effect by creating a localized region of significantly higher dielectric constant and other properties which in turn significantly increases the dielectrophoretic force and resulting torque, and lowers the response time by preferentially directionally orienting or channeling the non-uniformity of the electric field line generated by the entity or object target towards the laser beam region.
It is another object of the invention to improve the performance of previous dielectrokinetic detection and locator devices by using lasers to enhance the resulting dielectrokinetic effect of the devices.
These and other objects, and their attendant advantages, are achieved by the present invention, which provides an improved and enhanced dielectrokinetic locator device, comprising: a housing formed of a first dielectric material and having an interior with a second dielectric material therein; an auxiliary device utilizing laser emitted light oriented in a direction parallel to a longitudinal axis of the device; and a sinuous rod forming a handle, the rod having a first end extending from the interior of the housing and out a rear end of the housing, wherein an operator of the device grasps the housing and the handle and holds the device within range of an entity or object to be detected, such that the device reacts to a unique non-uniform electric field squared spatial gradient three-dimensional pattern exhibited by the entity or object to produce a dielectrophoretic force and a quantifiable manifestation of the force on the device that indicates specific direction relative to the object or entity.